Improve class nomenclature

[kheki4]

• Use "detection" and "tracking" words correctly everywhere: Detection is done on a frame, relying on that single frame, e.g. you only look once. Tracking is relying on detection output of the last frames.
• postfixes in class naming:
  1, window classes: window or dialog
  like RestorableQMdiSubwindow, or
  ? generalSettingsDialog -- holds the content
  2, the child widget that a window instance encapsulates: view
  singleCameraView, or
  stereoCameraView
  3, the custom widgets that view classes encapsulate: widget
  videoView -> cameraWidget